Abstract

In this paper, we report magnetostrictionmeasurements, on Fe-rich Fe–Al alloys and as functions of temperature from to room temperature (RT). From these measurements and elastic constant measurements, the tetragonal magnetoelastic coupling constants (’s) were calculated. Significant differences were found between our RT measurements and earlier magnetostrictionmeasurements for the higher Al concentration alloys (16.6%, 21.5%, 26.3% Al) and the alloy. Reminiscent of the temperature dependence of for pure Fe, magnetostriction changes with temperature are minimal for Fe–Al alloys having the disordered bcc structure (Al). In contrast, the alloy possessing the ordered structure shows an anomalous decrease in magnetostriction in with decreasing temperature. For the Fe–Al alloy system, the magnetoelastic coupling constant, , exhibits a peak at room temperature maximizing at 16.6% Al with a value of . For , was calculated to be at room temperature.

Received 12 September 2007Accepted 18 October 2007Published online 25 January 2008

Acknowledgments:

This work was supported by the Office of Naval Research Code No. 321MS, NSWCCD In-house Laboratory Independent Research Program, and Ames Laboratory. Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358. The authors would like to thank Dr. Brad Peterson for the temperature dependent elastic constant measurements of .